the firing order on a GM HEI is 1-8-4-3-6-5-7-2
The firing order for a 1973 corvette 350ci and the optional 454 is 18436572 Firing order remains the same for breaker point ignition as well as HEI electronic Position of #1 plug wire on distributor cap changes slightly when converting to HEI from a standard breaker point ignition system...............sfvrider242
They have to be in the firing order.
Is there a picture of distributor cap firing order for 2003 ford f150 4.2 engine
Which engine.
It depends on the firing order of the engine
get a book Run your spark plug wire from the #1 plug to the #1 lug on the distributor cap. Then follow the rest of the firing order going clockwise around the cap.
firing order from spark plug to the distributor cap
18436572
18436572
1,3,7,5,8,9,10
18436572
If it is a early model HEI. Then the inginition coil is bolted into the top of the distributor cap.